Funding Source: NSF Division of Ocean Sciences
Synopsis: Multiple stressors are currently impacting seagrass beds throughout the Gulf of Mexico and Caribbean, with two stressors having high potential for interactive effects: herbivory and coastal nutrient additions. Nutrient loading to the coastal zone is considered one of the leading causes of seagrass decline worldwide, but potential interactive effects from vertebrate grazers requires further study. This is because many mega-herbivores have recently rebounded from threatened or endangered status due to protective efforts, particularly in the Gulf of Mexico and Caribbean.
In addition, the tropicalization effect of northern Gulf seagrass communities from increasing sea temperatures has led to the expansion of home ranges for tropical fish species with herbivorous species such as parrotfish potentially driving enhanced grazing on turtlegrass (Thalassia testudinum) meadows. In this year-long study, herbivore exclusion cages are constructed and treatments of varying grazing intensities and nutrients are artificially maintained.
This project is part of a larger collaborative effort known as the Thalassia Experimental Network (TEN) that comprises partnerships with 11 institutions across 7 countries throughout the Gulf of Mexico and Caribbean that are conducting the experiment simultaneously. This experimental project will provide unique insight into large-scale comparisons of herbivory and nutrient addition effects on turtlegrass production.